Paper transport and paper stabilizing system for a printer plotter or the like

ABSTRACT

A vacuum transport belt for use in a multipass, multicolor raster printer has a vacuum attach means for providing a strong hold down vacuum force in the direction of paper travel for complete registration of a recording material with respect to a writing head and toner system. The vacuum attach means comprises a thin metal strip bonded to a transport belt such that the surface of the strip is substantially flush with the surface of the belt. A strong hold down vacuum is conducted through channels underneath the bonded strip to a series of closely clustered apertures which form a vacuum contact region on the strip. The force of the vacuum applied at the contact region and the substantially flush contact between the surface of the strip and the transport belt tightly seals the entire surface of the recording material to the transport belt, thereby registering the recording material precisely to the transport belt in an invariant desired alignment with a writing head and toner system.

This is a division of application Ser. No. 166,716, filed Mar. 11, 1986,now U.S. Pat. No. 4,878,071.

BACKGROUND OF THE INVENTION

This invention relates to a vacuum transport belt for providing improvedregistration of paper in a multipass, color raster line printer and thelike. The vacuum transport belt according to the present inventionregisters the paper firmly and accurately with a previously unattainabledegree of invariance with respect to a writing head and a series oftoning heads, while at the same time moving the paper relative to thestationary writing and toning heads.

The typical prior art color electrostatic plotters, which are ofmultipass nature, rely on a novel but unreliable system to achieveadequate color to color registration. This system consists of writingtick marks during the first black pass along both edges of the paper.During subsequent passes an optical system reads these marks and feedsback any dimensional or position of changes in the paper to the writingcontrol system and paper tracking system. This method works well forcorrecting the typical positional movement of the paper, but it cannotcorrect for paper growth in the direction parallel to the writing head.The registration marks of prior art systems that are plotted along theedges of the paper are unsightly compromises. Also, prior art web basedplotters require significant operator time to precisely align and threadthe paper into the plotter every time a new plot is to be generated. Thenecessity of printing registration marks also has the disadvantage ofgenerating wasted paper every time a new plot is completed.

The advent of the single pass web electrostatic plotter was an attemptto solve the registration problem and increase plotting speed. However,this method has the disadvantage of placing very tight constraints onthe toning system. In order to take advantage of the high potentialoutput speed, very little time is allowed for the toners to dryadequately. The single pass system also typically requires fourexpensive writing heads and four vector to raster controllers instead ofthe single head and single controller required by the multipass system.Registration can still be a problem, unless the four writing heads arevery precisely lined up relative to each other and the paper does notmove significantly during the printing process.

A more recent attempt at solving the paper stabilizing problem waspartially successful with the advent of a color electrostatic plotteremploying a rotating drum and helically scanning head and toning system.The salient advantage of the helical scanning drum system is that cutsheet paper is loaded on the drum automatically and held down by vacuum,while a small writing head and toning shoe helically write the image onpaper. This system has a disadvantage of a relatively small writing headand toning system which must be very precisely and compliantly mountedto the traveling carriage. Further disadvantages to helical scanplotting are overwhelming. For example, the adjacent band to bandwriting and toning "edge effects" are very difficult, if not impossible,to overcome. The rigid drum acting as a backing surface creates a veryharsh environment for the dielectric paper. Excessively high headpressures are required to achieve adequate writing quality, therebyresulting in damage to the dielectric coating of the paper.

In view of the foregoing disadvantages of prior art devices, it isapparent that what is needed is a paper transport system for anelectrostatic plotter or multipass color raster line printer whichenables precise and invariant registration of paper against a writinghead and series of toning heads while the paper is moved back and forthover the writing and toning assembly. Precise registration of the paperis necessary in order to obtain proper resolution and an improved degreeof color to color registration. It is known that superior and consistentcolor rendition from a raster type plotter requires a pass to passregistration of better than one half the dot spacing. At typically 400dots per inch, the accuracy required is 30 micrometers. Since dielectricpaper (or any unsealed paper) grows and shrinks with very small changesof humidity during a plotting cycle, it is obvious that it is veryimportant to keep the paper stabilized during subsequent plottingpasses. Another very important requirement of the electrostatic plottingprocess is that the head to paper interface must be very intimate (±1micrometer) across the whole width of the paper, without applyingexcessive pressure.

SUMMARY OF THE INVENTION

In order to overcome the foregoing disadvantages of known papertransport systems for multi-pass color raster line printers andplotters, the present invention provides a paper transport andregistration system which satisfies the conflicting objectives ofstabilizing the paper during the different plotting passes and providinga flexible, compliant interface between the writing head and paper.Another very important benefit of the present invention is that theeffective plotting resolution may be doubled without doubling the numberof high voltage drivers and the number of nibs on the writing head. Thisadvantage has potentially an enormous favorable economic consequence, asexplained infra.

The apparatus according to the present invention includes a flexible butstable, continuous belt which is stretched by two main rollers. Thisbelt has a vacuum attach area disposed across its full width forengageably contacting a leading and trailing edge of paper or otherrecording material disposed thereon. A unique feature of this vacuumattach area is the strong hold down force in the direction of papertravel provided by the vacuum. The force of the vacuum is of such anunexpected magnitude that vacuum also leaks under the paper along thelength of the belt, thereby keeping the entire surface of the paper invery intimate contact with the belt during the plotting cycle. The totalcircumference of the belt is slightly larger than the sheet of paper thesystem is designed to hold. An automatic feed and cutter system suppliesthe paper from a supply roll to the leading edge vacuum attach region,which then seizes the paper and stretches the paper onto the belt. Whena desired amount of paper has been metered out, the paper is cut andattached by vacuum onto the trailing edge. Once the paper has beenstretched onto the belt it is completely stabilized. Extraordinarystability results from the fact that the front or top surface of thedielectric paper forms basically a hermetic seal, and the backside ofthe paper is sealed by the belt. This enables all air to be drawn outfrom the contact region between the surface of the belt and the paper.Thus, the paper can now be precisely registered to the vacuum belt andmoved back and forth over the writing head and toners without anydistortion.

The apparatus according to the present invention provides a significantadvantage over the prior art in that it enables the writing nibs of amultipass color raster line printer to be tracked precisely to precedingpasses at one-half the distance between the writing nibs of prior artplotters, thereby achieving a doubling of the density of dots andsuperior resolution. For example, a first pass of evenly spaced dots iswritten by a writing head on paper which is completely stabilized usingthe transport system according to the present invention. Then, thewriting head can be shifted horizontally a distance equal to thediameter of one dot. Upon a successive pass of the writing head, anotherrow of dots now can be centered between the dots previously written. Theapparatus according to the present invention thereby provides theadvantage of achieving superior resolution with a far less complexwriting head and a smaller graphics dot memory than an expensive, singlepass high resolution plotter.

As will be explained, the present invention enables paper or othersimilar recording material to be mechanically registered to a very highdegree of precision. The paper is held rigidly by the vacuum beltwithout expansion or contraction due to humidity changes or mechanicaldeformation, as is so common in web type electrostatic plotters. Writingand toning can be accomplished without the paper going through anydistortion during successive passes of a writing head.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other advantages of the present invention may be appreciatedfrom the following detailed description of the preferred embodimenttogether with the drawings in which:

FIG. 1 is a perspective view of a first embodiment according to thepresent invention;

FIG. 1a is a perspective view of the embodiment of FIG. 1 with paper ina fully loaded position;

FIG. 2 is a perspective detail view of the vacuum transport beltaccording to the present invention;

FIG. 3 is a view of the underside of the vacuum attach means accordingto the present invention; and

FIG. 4 is a sectional view along section A--A of FIG. 3.

DETAILED DESCRIPTION

Referring to FIG. 1, an apparatus according to the present embodimentprovides a multipass color raster line plotter or printer 1 employingelectrostatic, thermal or other writing technologies. Electrostaticplotter 1 employs a flexible transport means 2 for registration thereonof a recording material 3.

In the preferred embodiment, transport belt means 2 is a continuous,thin, flexible but stable belt consisting of a stainless steel or nickelmaterial having a thickness of approximately 0.002-0.005 inches.Transport belt 2 is provided with a vacuum attach means 12 forstabilizing and for providing registration thereon of recording material3. In the preferred embodiment, transport belt 2 is suspended andstretched by two rollers 4a and 4b, respectively. Rollers 4a and 4bfunction as a means for passing the recording material 3 past a writinghead 5. The transport belt 2 is slightly larger than the means forrecording 3 which will be attached before the writing process begins Inthe preferred embodiment, the means for recording 3 comprisesconventional recording paper. The recording material or paper 3 isattached to the transport belt 2 by the vacuum attach means 12 whichinitially applies vacuum to the leading and trailing edges of the paper.The effect of the vacuum quickly spreads beyond the leading and trailingedges to thereby evacuate all of the air from between the paper and thetransport belt 2 such that the paper becomes perfectly registered to thetransport belt. This is achieved with the preferred embodiment byassuring that the recording paper has a plasticized, extremely smoothundersurface which is to be in contact with the top surface of transportbelt 2. The smooth surface of the recording material 3 interfacing withthe slick metal surface of the belt enhances the rigid adherence andregistration of the paper 3 to the belt 2 because the strong vacuumprovided by vacuum attach means 12 gradually removes all air from thespace between the smooth undersurface of the paper 3 and the top surfaceof the belt 2.

A full width writing head 5 is supported by an articulating structurerepresented schematically at 6. Articulating structures are well knownin the art. It will be appreciated that many forms of articulatingstructures could be implemented in the apparatus according to thepresent invention by a person skilled in the art without undueexperimentation. Accordingly, details of the articulating structure areomitted. The articulating structure 6 has a coarse up and down motion tomake clearance for a vacuum attach manifold 11. Articulating structure 6also produces a fine servo motion in the direction orthogonal to belttravel for moving the writing head 5 horizontally on the belt. Thewriting head 5 is also located in a region, which when engaged againstthe belt 2, is riding against the most compliant part of the belt 2.Means for applying toner to the recording material 3 also engages thebelt. In the preferred embodiment, the means for applying tonercomprises a toner assembly 7. Toner is applied by four toning stations,in the toner assembly 7 containing a black, cyan, magenta, and yellowtoner fluid. The toner assembly 7 is located adjacent to the writinghead 6 and also rides against a complaint part of the belt 2. Eachtoning station comprising toner assembly 7 has the ability to move upand down for selection as required during the sequential color passes.FIG. 1a shows the paper 3 in a fully loaded position on the belt 2 afterhaving been cut by cutting and feed mechanism 8. The paper 3 is nowready for plotting.

In operation, the belt 2 with the loaded paper 3 begins its first colorpass by momentarily coming to a stop with the leading edge of the paperbeing close to the writing head 5. The belt 2, along with the paper 3,make almost a complete revolution as the writing and toning are inprogress. The writing head 5 disengages from the paper before it reachesthe approaching trailing edge, and the vacuum belt 2 comes to a completestop with the toning system close to the trailing edge of the paper 3.The toning system 7 then drops away from the paper. The vacuum belt 2next makes a complete rewind and the process is repeated with the nextcolor, until all four color passes are completed. The paper 3 is thenstripped from the vacuum belt 2 and ejected during the final rewind. Ameans for feeding a new sheet of paper 3 from supply roll 10 and meansfor cutting the paper to a desired length are provided by cutting andfeed mechanism 8.

Referring now to FIG. 2, in the preferred embodiment, two vacuum attachmeans 12a, 12b are fixedly attached or bonded to the surface of vacuumbelt 2 by any convenient method. Vacuum attach means 12a, 12b areprovided to engage the leading and trailing edges, respectively of arecording material to firmly register the paper to the vacuum belt 2.

Vacuum attach means 12a, 12b comprise in the preferred embodiment a pairof flexible brass strips, approximately 0.005 inches thick which arebonded to form a substantially flush contact with the surface of thevacuum belt 2. Thus, the surface of each vacuum attach means 12a, 12b isvirtually integral against the surface of the belt 2. This is importantin order to achieve a seal tight relation between the undersurface ofthe paper 3, the top surface of the belt 2 and vacuum attach regions20a, 20b of vacuum attach means 12. The substantially integral surfaceformed by the belt 2 and extremely thin vacuum attach means 12 isessential to prevent the formation of any nonconformities which couldtrap air and degrade the intensity of the applied vacuum. The strips aredisposed across the width of the vacuum belt 2 and form a right anglewith the edge of the vacuum belt 2. A vacuum plenum or manifold 11 isdisposed on each surface of the vacuum attach means 12a, 12b and extendsalong the entire length of each the vacuum attach means 12a, 12b. Thevacuum plenum 11 has a means for attachment to a vacuum source as shownby the vacuum hose 14 in FIG. 1.

Referring again to FIG. 2, the vacuum plenum provides a vacuum for theattach regions 20a, 20b of the vacuum attach means 12a, 12b which comein contact with and hold down the leading and trailing edges of thepaper. The vacuum plenum forms a raised rectangular vacuum chamber whichextends along the width of the vacuum belt 2. The outer sides of thevacuum plenum are disposed orthogonally with respect to the direction oftravel of the vacuum belt 2. The outer sides of the vacuum plenum 11 aredisposed in combination with each vacuum attach regions 20a, 20b toprovide a stable means for initial alignment and registration of theleading and trailing edges of the paper to the vacuum belt 2. That is,when beginning the writing operation, the paper can be aligned againstthe outer sides of the vacuum plenum and thereby registered initially ina proper position with respect to the writing head 5 and toner assembly7. The application of vacuum to the underside of the leading andtrailing edges of paper 3 in contact with vacuum attach regions 20a, 20bthen completes the registration of the paper to the belt 2.

Further details of the vacuum attach means are shown in FIGS. 3 and 4.FIG. 3 shows the underside of a vacuum attach means 12. Referring toFIG. 3, vacuum plenum 11 is disposed over a series of vacuum receivingbores 15. Each bore 15 has a connection through an associated channel 17to a series of primary vacuum applying apertures 22. The channels 17provide a means for transferring essentially all of the vacuum from thevacuum plenum 11 to the vacuum attach region 20. It will be appreciatedthat the channels 17 are extremely shallow in order to thereby transferthe vacuum beneath the thin vacuum attach means 12 so as not tointerfere with the seal tight relation of the recording material 3 tothe substantially integral surface of the vacuum attach means 12 and thebelt 2. The primary vacuum apertures 22 are disposed to form the vacuumattach region 20 of the vacuum attach means 12. Primary vacuum apertures22 provide a means for applying a strong hold down vacuum to the leadingand trailing edges of the recording material. In the preferredembodiment, primary vacuum apertures 22 are a series of closely spacedparallel rows of apertures. Each row of apertures is connected with anassociated channel 17 through which vacuum is transferred from thevacuum plenum 11. Primary vacuum apertures 22 directly contact theleading and trailing edges of the paper as other recording materialdisposed on the surface of the belt.

The channels 17 are photolithographically etched in the underside of thevacuum attach means 12 or are otherwise formed by any conventionaletching process. When the vacuum attach means 12a, 12b are bonded to thevacuum belt 2, the channels 17 provide sealed vacuum passages in theinterior of the vacuum attach means.

It will be appreciated that the vacuum produced in the vacuum plenum 11is transferred to the primary vacuum applying apertures 22 of the vacuumattach means 12 without any perceptible leakage. The primary vacuumapertures 22 come in sliding contact with the underside of the paper 3as it is initially registered against the sides of the plenum 11. Thevacuum produced by the primary vacuum apertures 22 is particularlystrong and is provided in the direction of paper travel. It has beenfound that this vacuum unexpectedly provides not only a precise,invariant registration of the leading and trailing edges of the paper tothe belt, but the vacuum applied by the primary vacuum apertures 20 alsotravels progressively under substantially the entire surface of therecording material, thereby rigidly adhering an entire sheet of paper 3to the vacuum belt 2.

It has been found that the spread of vacuum between the lower surface ofthe recording material 3 and the top surface of the belt 2 is enhancedby the use of a metallic material for the transport belt 2. The slick,smooth surface of a metallic belt as used in the present inventionformerly would have been perceived as a detriment to the properregistration of paper in an electrostatic line plotter. It was notdeemed practical to stabilize paper on a metal transport belt becausethe slippery, polished surface of the metal was believed to precludeproper adhesion of the paper to the surface of the metallic belt.However, with the flush, substantially integral surface formed bybonding the thin vacuum attach strips 12a, 12b to a metallic vacuum belt2 of the present invention, the slick metal surface has been found toenhance the application of vacuum to the paper 3 by eliminatingnonconformities which would create air pockets. Accordingly, the vacuumapplied by the vacuum attach means 20 actually spreads unimpeded betweenthe slick metal surface of the belt and the overlying paper to form anair tight contact between the paper and the metallic belt. In thisregard, superior registration of paper to the belt is achieved when theunderside of the paper 3 in contact with the slick surface of themetallic belt is plasticized or otherwise free of porous regions whichcould allow air flow and reduce the vacuum.

With regard to transportation and stabilization qualities, it has alsobeen found that metal is the preferred material for the vacuum transportbelt 2 of the present invention. In a so called web type paper transportsystem for an electrostatic plotter or the like, the paper or recordingmaterial is always subject to a certain amount of pulling and distortionduring the writing process. The paper also grows and shrinks in size dueto changes in humidity. Additionally, a web transport method of theprior art is subject to some distortion in operation when transportingthe paper. All of the foregoing factors degrade the proper registrationof the recording material to the transport belt and result in poorresolution and poor color to color registration.

In contrast, the metal belt of the present invention does not distortwhen pulled and thereby provides a stable base by which the vacuumattach means 12a, 12b of the present invention may achieve preciseregistration of the paper at all times during the writing scheme.Distortion may be reduced or eliminated because a metal belt iscompliant in the vertical or Z axis while maintaining rigidity in the Xand Y axes. The registration of paper achieved by the apparatusaccording to the present invention is extremely important in anelectrostatic plotter or printer because of the precise tolerance whichmust be maintained between the writing head and the paper surface. In aconventional electrostatic plotter, the writing head must be maintainedin intimate contact with the paper across its entire width. Theclearance between the end of the writing head and the top surface of thepaper is typically much less than 1/10000 of an inch.

The compliant nature of the metal belt in the Z axis (verticaldirection) and its rigidity in the X and Y axes provides significantadvantages over prior art paper transport systems. The property ofcompliancy enables precise registration of the paper even with changesin alignment between the writing head and the paper surface in contacttherewith due to differential thermal expansion and changes in thesurface texture of the paper as may be caused by increased humidity. Themetal belt of the present invention stabilizes the paper, and does notdistort, grow or shrink appreciably with changing temperature andhumidity. This enables a more precise registration of paper than waspreviously possible. The foregoing advantages of the metallic belt usedin present invention also enhance color to color registration andresolution.

The apparatus according to the present invention achieves a moreconstant and precise registration of paper to the paper transport andwriting system than was previously possible in a multipass electrostaticplotter. This has the further advantage of enabling the presentinvention to achieve a doubling of the density of dots which can beproduced by an ordinary writing nib in a prior art electrostaticplotter. This enables the present invention to achieve superiorresolution which formerly would have been possible only by employingvery expensive, high resolution writing heads. The doubling of thedensity of dots is made possible by reason of the complete registrationof paper to the entire surface of the vacuum belt 2 as described above.

The improved resolution of the present invention occurs as follows. Thewriting head of a multipass electrostatic plotter makes a first passover the paper and produces a first set of dots from the writing nibs(not shown). On a second pass over the paper, the present inventionenables the writing head to be moved one half of the distance betweenthe writing nibs. This achieves a doubling of the dots because thewriting nibs print a second set of dots which are precisely tracked tothe first set and are spaced at only one half of the ordinary distance.For example, on a second pass, the writing nibs may be tracked with suchprecision as to place another row of dots between the dots alreadywritten on the first pass.

A conventional writing head typically prints 200 dots per inch. It isknown that paper will grow and shrink a maximum of 4 dots laterallywithout being stabilized by a metallic vacuum belt according to thepresent invention. As a result, previous devices could not track awriting head to a previous pass at the present distance of only one halfof the distance between the writing nibs. The present invention therebyachieves superior resolution with inexpensive writing heads by enablinga standard writing head to make successive passes over the paper whichare spaced only a very small distance apart. Note that in prior artdevices, such enhanced resolution could be achieved only by the use ofvery expensive writing heads having double the number of nibs. Thus, thepresent invention is able to achieve the same enhanced resolution andimage clarity which formerly could be obtained by an expensive, highresolution writing head.

The apparatus according to the present invention also enables doubleresolution color plotting to be achieved simply and without the expenseof a more complicated writing head, due to the high degree of paperstability guaranteed by the vacuum belt 2 of the present invention.Prior to each color and writing-toning pass, a writing-only pass is madewith the head shifted laterally by one half dot. The subsequent writingand toning pass is done with the writing head and toning system innormal position. The writing head and raster image memory complexity arecut in half with this method, compared with conventional techniques.

Referring now to FIG. 4, a method for manufacturing the vacuum attachmeans 12 of the present invention is explained as follows. A thin,flexible strip of material 12 is etched from both sides employingstandard lithographic techniques. In the preferred embodiment, thevacuum attachment means 12 is comprised of a brass strip approximately0.005 inches thick. The paper contacting top surface A of the brassstrip is etched to a depth of 0.001 to 0.002 inches. The etchingproduces a single row of apertures and, spaced apart from the singlerow, multiple rows of apertures disposed in parallel. The single row ofapertures forms the vacuum receiving bores 15 which are overlain by thevacuum plenum or manifold 11 as shown in FIGS. 2 and 3. The multiplerows of apertures comprise the vacuum attach region 20 consisting ofprimary vacuum holes 22 which provide the vacuum hold down force forregistration of the entire surface of the paper to the belt 2.

The underside of the thin brass strip forming the vacuum attach means 12is etched to a depth of 0.003 to 0.004 inches. This etching produces aseries of channels disposed in parallel along the entire length of thestrip. Each channel connects a vacuum bore 15 with the series ofparallel primary vacuum applying apertures 22 as shown in FIG. 3. Theprecise arrangement of the channels is not important. When the undersideof the strip is bonded to the metal vacuum belt 2, the channels etchedtherein provide a series of air tight chambers for transferring thevacuum from the vacuum plenum 11 to the primary vacuum applyingapertures 20. Thus, the vacuum can be transferred from a vacuum sourceto the underside of the recording material without any appreciableleakage whatsoever. This produces an extraordinarily strong vacuumholddown effect in the area of the vacuum attach regions 20a, 20b whichprogressively spreads under the entire surface of the paper to therebyimmovably register the paper to the vacuum transport belt 2.

Several alternate paper-to-belt attach schemes are possible. One is tosignificantly increase the vacuum hold down force over the whole area ofthe paper, not just under the leading and trailing edge. This can beachieved by incorporating micro groves that are about 1 to 25 micronsdeep and 50 to 200 microns wide over the whole area of the belt 2 underthe active paper area. In this embodiment, the pattern of grooves on thebelt also must be configured such that a vacuum applied to the groovesproduces a coefficient of friction close to unity between the belt andthe paper.

Another possible paper attach scheme is to construct the leading ortrailing edge attach area of the transport belt in a way not requiring avacuum system. This could be done by incorporating a mechanical attachmechanism which clamps the leading and trailing edges of the papersecurely in the direction of travel. Even though this is not thought tobe as stable as the present vacuum attach system, it can certainly beused in a lesser product.

While the invention has been described in connection with what ispresently considered to be the most practical and preferred embodiments,it is to be understood that the invention is not limited to thedisclosed embodiment but, on the contrary, is intended to cover variousmodification and equivalent arrangements included within the spirit andscope of the appended claims.

What is claimed is:
 1. An improved, high resolution plotter, printer orthe like incorporating a transport belt means for invariant registrationof a recording material with respect to a writing head comprising:arecording material; writing means disposed for printing information onsaid recording material; toning assembly means operatively connectedwith said writing means enabling said writing means to selectively applycolor fluid to said recording material; transport means including a belthaving an attach means for providing a vacuum to the entire surface ofsaid recording material adjacent said belt such that said recordingmaterial is registered in invariant alignment with respect to saidwriting means and said toning assembly means; drive means for passingsaid transport means past said writing means and said toning assemblymeans.
 2. An apparatus as in claim 1 wherein said transport meansincludes a vacuum attach means having a surface flush with the surfaceof said belt for applying a strong vacuum hold down force in thedirection of travel of said transport means to said adjacent surface ofsaid recording material disposed thereon, thereby providing invariantregistration of said recording material with respect to said writinghead means and said toning assembly means.
 3. An apparatus as in claim 2wherein said vacuum attach means for applying a vacuum hold down forceto said surface of said recording material comprises:an elongate, thinstrip disposed substantially across the width of said belt having apaper holding surface for engaging a leading and trailing edge of saidrecording material thereon; a vacuum manifold means having a connectionwith a vacuum source and mounted on said paper holding surface of saidstrip for providing a vacuum thereto; a series of vacuum receivingapertures extending through said strip for receiving said vacuumprovided by said vacuum mainfold means; a series of vacuum applyingapertures spaced apart from said vacuum receiving apertures and therebyforming a vacuum contact region for engaging said recording material;means for transferring vacuum from said vacuum manifold means to saidvacuum contact region.
 4. An apparatus according to claim 3 wherein saidmeans for transferring vacuum comprises a series of parallel channelsconnecting said vacuum receiving apertures with said series of vacuumapplying apertures forming said vacuum contact region, said parallelchannels being provided in an opposed surface of said strip contactingsaid transport belt such that when said strip is bonded to saidtransport belt, said channels form fully enclosed passages for evenlytransferring vacuum from said vacuum manifold means to said vacuumcontact region.
 5. An apparatus as in claim 2 wherein said belt iscomprised of a flexible material which is compliant in the axisorthogonal to paper travel and rigid in the direction of paper travel tothereby stabilize said recording material disposed thereon fromdimensional changes due to humidity and thermal expansion.
 6. Anapparatus as in claim 5 wherein said belt consists of a flexible metalmaterial.
 7. An apparatus as in claim 5 wherein said belt consists of aflexible material having a metallic paper holding surface.
 8. Anapparatus according to claim 6 wherein said belt is provided with asmooth surface for conformably contacting the entire surface of saidrecording material disposed thereon to thereby facilitate a progressiveincrease in the coefficient of friction between the surface of saidrecording material and said belt.
 9. A vacuum hold down means forprecise registration of a recording material with respect to a writinghead and toner assembly in a plotter, printer or the like comprising:atransport belt having a paper holding surface for forming a matingconfiguration and providing an airtight seal with a recording materialdisposed thereon; vacuum attach means disposed on said paper holdingsurface of said transport belt for providing a strong vacuum hold downforce to the leading and trailing edges of said recording material inthe direction of paper travel.
 10. An apparatus as in claim 9 whereinsaid transport belt is composed of a material characterized bycompliance in an axis orthogonal to paper travel and by rigidity in thedirection of paper travel.
 11. An apparatus as in claim 9 wherein saidvacuum attach means comprises an extremely thin elongate strip having asurface bonded to said transport belt and an opposed surface disposed insubstantially integral contact with said paper holding surface of saidtransport belt to thereby form an airtight seal between said transportbelt and said recording material disposed thereon.
 12. An apparatus asin claim 11 wherein said elongate strip further comprises:a first seriesof apertures extending therethrough for receiving an applied vacuum froma vacuum source; and a second series of closely clustered aperturesextending therethrough for providing a vacuum contact region forcontacting and registering a leading and trailing edge of said recordingmaterial disposed thereon; and transfer means disposed in said surfaceof said strip bonded to said transport belt for transferring vacuum fromsaid first series of apertures to said second series of apertures. 13.An apparatus as in claim 12 wherein said transfer means furthercomprises multiple channels provided in said surface of said stripbonded to said transport belt for connecting said first series of vacuumreceiving apertures with said second series of closely clusteredapertures to thereby provide a vacuum to said vacuum contact region. 14.An apparatus as in claim 9 wherein means for providing a vacuum has aconnection with a vacuum source and is disposed on said opposed surfaceof said vacuum strip for applying a vacuum to said first and secondseries of vacuum receiving apertures.
 15. A method for fabricating avacuum attach means for registration of a recording material on atransport belt with respect to a writing head in a plotter, printer orthe like comprising the steps of:etching a first series of vacuumreceiving apertures in a paper holding surface of a thin metallic stripalong the length thereof; etching a second series of closely spacedvacuum attachment apertures in said paper holding surface of said stripalong the length thereof, and spaced apart from said first series ofapertures by an intervening area, to thereby form a vacuum contactregion on said paper holding surface of said strip for conformablyadhering a recording material thereto; etching a series of channels inan opposed surface of said strip to a depth sufficient to contact saidfirst and second series of apertures, while not penetrating though saidintervening area of said paper holding surface separating said first andsecond series of apertures, and thereby connecting by means of eachchannel said first series of apertures with said second series ofapertures; bonding said opposed surface of said strip containing saidchannels to the surface of said transport belt to thereby fully enclosesaid channels and from tightly sealed vacuum chambers disposed beneathsaid paper holding surface of said strip for transferring vacuum fromsaid first series of apertures to said second series of apertures.
 16. Amethod as recited in claim 15 further comprising the step of:providing avacuum plenum extending along the paper holding surface of said strip intightly sealed contact with said first series of vacuum receivingapertures for providing a vacuum thereto.
 17. An improved, highresolution plotter, printer or the like incorporating a continuoustransport belt means for maintaining a recording material disposedthereon in invariant registration with respect to a writing headcomprising:a recording material; a writing means disposed for printinginformation on said record material; a flexible transport belt meanscharacterized by a metallic or extremely smooth paper holding surfacefor supporting and maintaining said recording material in invariantregistration thereon with respect to said writing means, said transportbelt means having compliancy in an axis orthogonal to the direction ofpaper travel and rigidity in the direction of paper travel; roler meansfor passing said continuous transport belt and said recording materialin a substantially complete revolution past said writing means; attachmeans for progressively removing substantially all of the air betweensaid paper holding surface of said transport belt and said recordmaterial disposed thereon such that an airtight seal is provided betweensaid paper holding surface of said transport belt and said recordmaterial and said record material is thereby maintained in invariantalignment with respect to said writing means.
 18. An improved paperstabilizing system for a plotter printer, of the like having acontinuous transport belt for supporting a recording medium withinvariant registration for one or more revolutions past a writing headcomprising:a writing head means disposed for imprinting information upona recording medium; a continuous transport belt means having a uniform,extremely smooth paper holding surface for eliminating air trappingunconformities and for stabilizing said recording medium thereon for oneor more revolutions past a writing head; means for forming an airtightseal between said smooth supporting surface of said belt and saidrecording medium and for eneabling a vacuum to spread between said paperholding surface of said belt and said entire surface of said recordingmedium to invariantly stabilize said recording medium with respect tosaid writing head means.
 19. An apparatus according to claim 18 whereinsaid means for forming an airtight seal includers an extremely thinvacuum attach means disposed flush with said paper holding surface ofsaid belt for providing a vacuum which spreads beneath the entiresurface of said recording medium supported on said belt to thereby holdsaid recording medium on said belt with an invariant degree ofstability.
 20. In a plotter, printer, or the like, an improvedcontinuous transport belt means for immovably stabilizing a recordingmedium such as paper for one or more revolutions past a writing headcomprising:a continuous transport belt means having an extremely slick,uniform paper holding surface for supporting said recording mediumthereon; means for providing an airtight interface between said slicksurface of said belt and said adjacent recording medium supportedthereon such that all air is removed from between said belt and saidrecording medium and said recording medium is thereby immovably adheredto said slick surface of said belt.
 21. An apparatus according to claim20 wherein said means for providing an airtight interface include attachmeans for attaching a leading and trailing edge of said recording mediumto said belt and means for pressing the remaining portion of saidrecording medium to said belt to progressively remove all air frombetween said recording medium and said belt.